Just four days after a federal judge approved a settlement in the e-books price fixing case, HarperCollins is already selling its titles at discounted prices with a number of online retailers, including Amazon, Barnes & Noble, and BooksonBoard.

“HarperCollins has reached agreements with our e-retailers that are consistent with the final judgment,” HarperCollins spokeswoman Erin Crum said in a statement. “Dynamic pricing and experimentation will continue to be a priority for us as we move forward.”

According to Jane Litte, who first noticed the changes and blogged about it on the romance blog Dear Author, HarperCollins e-books have been discounted 10 percent to 20 percent. That means readers can get books like Daniel Silva’s “The Fallen Angel” and Hope Solo’s “Solo” for $9.99. Titles that are discounted are labeled "Sold by HarperCollins," booksellers newsletter Shelf Awareness points out, while titles still under the agency model are tagged “Price set by Penguin.”

HarperCollins is the first of the three publishers who settled to renegotiate its contracts with retailers as required by the terms of the settlement. (The settlement was approved last week by a federal judge and includes Hachette Book Group and Simon and Schuster. Apple, Macmillan, and Penguin did not settle and face trial next summer.)

As Good E-Reader pointed out, “It is a savvy business move by HarperCollins to be the first company to reach a new agreement with many retailers. It may see increased sales in the time it takes other companies to iron out their own plans of action.”

The impacts of the settlement – and HarperCollins’s decision to get out in front – could be big. For HarperCollins, it means a direct, if short-lived, competitive advantage and one that will affect sales and bestseller rankings. For publishers, it’s a loss in a much larger battle about pricing in which millions of dollars are at stake. For Amazon, it’s a major victory that allows the online retailer, for a couple years at least, to set the prices of many more e-books than it could in the past and therefore beat out competition.

And of course, for consumers, at least in the short-term, it means lower e-book prices.

What does this mean for the health of the marketplace as a whole? The jury’s still out, but CNET’s Charles Cooper offers this thought: “Last week, HarperCollins, Hachette, and Simon & Schuster cut a deal with the government to settle allegations that the book publishers had colluded with Apple to fix the price of e-books. If you believe the government's charges, the book publishers were trying to prevent Amazon from discounting them to death.”

“Now,” he writes “it's back to the future. Earlier today came word that Amazon had returned to form, discounting HarperCollins e-books titles.”